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This is an application module describing using Logistic Regression to solve a detection problem in Particle Physics: Detecting the top quark.


High-energy particle physics experiments today usually involves colliding beams of particles accelerated to tremendous energies and then studying the “shrapnel" that is created. The goal of such experiments often involves the discovery of new particles that are created when two common particles from the beams collide. Unfortunately, these new particles are so short-lived that they cannot be observed directly. Instead, the existence of such particles is inferred from patterns in the “shrapnel" that is formed when they decay into other particles. It is the properties of these secondary particles that are measured in detectors such as those at the Large Hadron Collider (LHC).

To discover a new particle, physicists use computer programs that have been programmed with theoretical models to simulate large numbers of random particle collisions. The models are tuned so as to generate two sets of collision “events": one set is compatible with the particle existing in nature and the other is compatible with the null hypothesis. The characteristics of the sets of simulated events are then compared with real events from a live experimental detector.

Because of the complicated nature of the events and the large amount of data involved, machine learning has been investigated to help with the classification problem of determining what kind of particles are initially produced for each event. If we can train classifiers on simulated data to be effective at distinguishing events that are associated with interesting particles from uninteresting background events, we will likely be able to use such classifiers to confirm or deny the discovery of these particles in real data. The existence of more effective classifiers decrease the amount of real data that must be collected to obtain a statistically significant result. Given the large expense of operating particle colliders and the power of modern computers, acquiring more effective classifiers is an important problem for particle physicists.

Project goal

The project goal is to construct a classifier that is efficient at verifying the existence of a top quark in a set of simulated collision events. Top quarks are good particles for investigating classifiers because they are very rare and very hard to detect but have already been proven to exist. Efficiency is defined by the beam luminosity needed to detect the existence of top quarks with 5 σ of statistical significance, the “industry standard" for particle physics. Beam luminosity is directly proportional to the number of collisions, and thus the operating time of the experiment, and thus the cost, so lower required luminosity is better.

Top quarks can be created by a number of different pathways, and each pathway creates a different pattern of decay products measured by the detectors, real or simulated. This project focuses on only one particular pathway which results in the creation of a top quark and its anti-particle in what are known as “t-tbar" events.

Questions & Answers

I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
How can I make nanorobot?
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Source:  OpenStax, Introductory survey and applications of machine learning methods. OpenStax CNX. Dec 22, 2011 Download for free at http://legacy.cnx.org/content/col11400/1.1
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